PALM KERNEL SHELL IMMOBILIZED CALCIUM ALGINATE BEADS AS ADSORBENT FOR Cu2+ IONS

• Main Author: WAHYU (NIM: 20513501) , YUHELMI
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20637
• Institution: Institut Teknologi Bandung

Pollution of heavy metal ions in the environment is very dangerous because it is toxic. One of the heavy metal ions is copper ions (Cu2+). Exposure to Cu2+ ions in the body can cause skin irritation, kidney disease, and even lung cancer. Therefore, it is important for the reduction of Cu2+ from wastewater. Adsorption is one of the most commonly used methods to remove heavy metal ions from wastewater. Heavy metal adsorption using biomass more economically, environmentally, and effective enough to reduce the levels of heavy metals in wastewater. One of the abundant biomass in Indonesia is palm kernel shells. However, the use of palm kernel shells powder as adsorbent has some shortcomings which are difficult to be separated after the adsorption process and can cause a blockage when applied to the column. The weakness can be overcome by encapsulating biomass using Alginate. Alginate is a polysaccharide that is commonly used as a matrix and form a gel when it binds with divalent cations such as Ca2+ through crosslinking. In this study, the adsorbents researched are Ca-alginate (CA) and encapsulated palm kernel shells by Ca-alginate (CA-CKS). The CA and CA-CKS are characterized using FTIR and SEM-EDS. Furthermore, the optimization of Cu2+ adsorption performance is carried out on various parameters using the batch method. These parameters are pH, contact time, adsorbent mass and initial concentration of Cu2+. The experimental results show that the optimum condition of adsorption of Cu2+ on CA and CA-CKS i.e. at pH 5, a contact time of 120 minutes, 0.05 gram of adsorbent mass and maximum adsorption capacity respectively at 61.68 mg/g and 63.15 mg/g. It shows that the performance of Cu2+ adsorption on CA and CA-CKS do not have much difference. Based on the results of FTIR and SEM-EDS characterization for those two adsorbents before and after the adsorption process, it is assumed that the functional group involved in the binding of Cu2+ is a carboxylic group and its main mechanism is ion exchange. The process of adsorption of Cu2+ by those two adsorbents followed the Langmuir isotherm model and pseudo second order kinetic. Langmuir isotherm model assumes the process of adsorption of Cu2+ on CA and CA-CKS is monolayer and homogeneous, whereas the pseudo second order kinetic model assumes the process of adsorption of Cu2+ occurs chemically, where there is one adsorbate Cu2+ attached to two sides of the active adsorbent. The binary and mixture adsorption system are conducted by the batch method using ion mixture of ions Cd2+, Pb2+, and Ni2+ in the ratio of 1: 1 which indicates that the adsorbent CA and CA-CKS do not selective in one type of metal. The ability of the metal ions to be bound on those two adsorbents is influenced by the physical and chemical properties of each ion. The study of the column by the circulation method on offline system shows the minimum time required to adsorb all metal ions Cu2+ from 250 ml of Cu2+ 1 ppm using a 0.5 g CA-CKS is 480 minutes. Desorption of metal ions Cu2+ is conducted using a solution of 20 mL HNO3 1 M with preconcentration factor of 12.5 times. The reuse of the adsorbent indicates that the adsorption-desorption process in the CA-CKS is able to be done as much as three times with the desorption percentage in cycle 1, cycle 2 and cycle 3 respectively are 91.48%, 83.38%, and 81.93%.